This invention relates to an improved electrophoresis device.
Electrophoresis gels are widely used for separating and analyzing biomolecular materials such as proteins and nucleic acids, for example. A gel medium, such as polyacrylamide, agarose or combinations thereof, is commonly disposed between a pair of electrically-insulating, liquid impermeable sheets such as glass or plastic plates which are held in spaced-apart, opposing relationship by insulating spacers or the like. During use, sample liquids, which are to be subjected to electrophoresis, are placed, layered or injected into sample wells at the top of the gel medium and electrophoresis is begun by applying electrical power to the gel medium.
In the prior art, sample wells have been formed by inserting a comb shaped plastic member into the gel solution while it is still a liquid. After polymerization has occurred, the comb is removed and the sample wells are formed in the location where the teeth of the comb resided in the gel. The formation of consistently good sample wells in gels where the concentration of acrylamide is low has been generally unreliable and inconsistent using this technique. Low concentrations of acrylamide or other media provides a wider spectrum of biomolecules to be separated, particularly large size biomolecules.
Another technique that has been used to form sample wells is to first pour a gel with a flat top surface. A plastic insert is then placed on top of the surface to form the wells. The plastic insert, however, has not proven reliable in sealing the wells against leakage. Sample liquid leaks past some of the wells and contaminates adjoining wells.
The prior art techniques generally rely upon the fits and clearances between the plastic comb or insert and the slot or opening provided between the glass plates in order to accommodate them. The slot or opening between the glass or plastic plates is generally created by spacers which are typically made from plastic sheet material. The slot openings or gel thickness tolerances between the combs and spacers can vary significantly enough to negatively affect the formation of the sample wells using prior art techniques for forming sample wells.
It will be apparent that the prior art has thus far failed to provide a reliable, economical solution to forming consistent sample wells particularly in large size gels and gel media of low concentration or poor characteristics. Instead, manufacturers of precast (ready made) gels have resorted to producing gels with flat tops, thus leaving to the individual researcher the task of forming the sample wells on top of the resolving gels. The researcher will ordinarily utilize either one of the above described techniques for forming the wells.
It is therefore an important object of the invention to provide an improved electrophoresis device employing a gel medium together with preformed sample wells wherein the sample wells are of consistently good quality. Another object of the invention is to provide such an improved electrophoresis device which eliminates high rejection rates of precast gels due to faulty wells in order to economically justify the production of precast or ready made gels on a large scale commercial basis.